4522 PREVALENCE OF CHRONIC KIDNEY DISEASE IN PREGNANCY: A UK POPULATION STUDY

Abstract Background and Aims Women with chronic kidney disease (CKD) are at greater risk of adverse pregnancy outcomes. Historically CKD in has been proposed to affect 3% of all pregnancies (0.13% with ‘moderate to severe’ CKD) but is based on expert opinion and numbers affected are propose to rise due to the rise of maternal obesity and age and could impact on service planning. However, there are no accurate estimates of CKD prevalence in pregnancy. This study aimed to investigate how many pregnancies may be affected by CKD, according to disease severity, in a UK population cohort. Method Routinely collected pregnancy data from three NHS Trust hospitals in Kent (UK) between 2010 and 2020 were extracted with Research Ethics Committee approval (19/LO/1242 and 18/SC/0158). Local laboratory and health care records were linked and used to identify women between 18 and 50 years of age with a confirmed eGFR measurement (Chronic Kidney Disease Epidemiology Collaboration 2009 without ethnicity correction) within two years prior to conception, and no current pregnancy recorded at the time of sampling. Baseline characteristics and prevalence of CKD at different stages were described. Results A total of 76, 755 pregnancies were recorded between 2010 and 2020, including 14,257/76,755 (18.6%) pregnancies with preconception eGFR (median eGFR 115 ml/min/1.73 m2 (IQR 21)). There were 1,184/14,257 (8.3%) pregnancies with a preconception eGFR